Groovy wires could detect disease and explosives

A breakthrough by a group of researchers in the UK and in Spain could pave the way for much improved disease detection, and detection of explosives.

T-Rays, with a frequency in the region of a thousand billion cycles per second, inhabit the part of the electromagnetic spectrum between micro and infrared waves. Many complex molecules have very distinct reactions when probed with radiation of this energy, the researchers say, making T-Rays potentially very useful in detecting explosives and in the quality control of prescribed medication.

However, the current state of the art is such that it is very hard to focus them with mirrors or lenses, meaning they are of little practical use.

What this team of Anglo-Spanish scientists has done is find a way to focus the T-Rays onto a point just millimetres across.

An ordinary wire does not transport T-Rays very well, but engraving a metal wire with a series of tiny grooves, the team found that it was possible to control the flow of the terahertz radiation. By tapering the corrugated wire as well, the researchers were able to focus the rays as well as direct them.

Dr Stefan Maier, of the University of Bath's department of physics, who leads the research, described the technique as a "significant breakthrough".

"Metal wire ordinarily has a limited ability to allow T-Rays to flow along it, but our idea was to overcome this by corrugating its surface with a series of grooves, in effect creating an artificial material or 'metamaterial' as far as the T-rays are concerned.

"In this way, the T-Rays can be focused to the tip of the wire and guided into confined spaces or used to detect small objects, with important implications for disease detection or finding explosives that are hidden."

The team's findings are set out in the current journal Physical Review Letters. ®